Welcome back to our lecture series on the course Ecology and Environment, in this lecture
we will discuss issues related to Sustainable Water Management in urban areas.
First some definitions regarding what is an urban area, in the context of India, Statutory
Towns are defined as all places with a municipality, corporation, cantonment board, notified town
area, committees, etcetera.
A Census Town is defined as all villages with a minimum population of 5,000 persons in the
preceding census, at least 75% of male main working population engaged in non-agricultural
activities, and a population density of at least 400 persons per square kilometers.
An Urban Agglomeration is defined as a continuous urban spread comprising one or more towns
and their adjoining out growths.
In Outgrowth is defined as area around the core city or town, such well recognized places
like railway colony, university campus, port area etcetera, lying outside the limit of
town.
Here we are concerned with the water management in urban agglomerations and urban areas.
Now if you look at the population that is rural urban distribution of population in
India, in 1961 the total population was 439.2 million people out of that 360.3 million people
lived in rural areas and 78.9 million people lived in urban areas basically urban population
amounted to 18% of the population, and in 50 years that is 2011 the total population
has increased to 1210.6 million, out of that 833.5 million are living in rural areas whereas
377.1 million people are living in urban areas.
Now the percentage of urban population is 31.1%, so it has increased from 18% to 31.1%
and it is expected to increase much more in years to come, so this is going to put some
kind of a stress on our water resources in urban areas, and we need to tackle that, there
are 475 urban agglomerations in India as per 2011 census,
this is 23.7% increase in one decade, in the last one decade that is 2001 to 2011 that
has been an increase of 23.7% in the number of urban agglomerations and the largest urban
agglomeration in India is Greater Mumbai which has 18.5 million people living in it, followed
by Delhi were 16.3 million, Kolkata 14.1 million, Chennai 8.7 million and Bangalore 8.5 million
these are the 5 largest cities in India and the water problem in these cities one has
to tackle.
If you look at the water availability in India, in 1951 we had 5,177 meter cube of water per
person per year and that has reduced to 1820 meter cube per year per person by 2001 and
it is expected to decrease to 1341 meter cube per year per person is because many of the
water resources are dwindling as well as the population is increasing.
By 2050 the water availability is going to be expected to be 1140 meter cube per year
per person, this is as per the estimates made by Ministry of Water Resources, River Development
and Ganga Rejuvenation of Government of India.
If you look at the demand in billion cubic meters, in 2010 the demand was 813 billion
cubic meters and in 2025 the demand is expected to increase to 1093 billion cubic meter and
2050 the anticipated demand is 1447 is again the estimates made by the Ministry of Water
Resources, River Development and Ganga Rejuvenation of Government of India, on one hand the demand
is increasing and per-capita availability of water is decreasing.
Now what are the drivers of increase in the water demand?
First and foremost there is a direct increase in demand due to increase in population, the
population is expected to increase from 1.2 billion in 2010 to 1.6 billion in 2030, so
this increase in population definitely is going to increase in the water demand, then
in some places there is a demand aggregation as the cities grow, they're more and more
people are coming to the cities, more and more places are getting urbanized, so there
is a demand aggregation at some points because of this urbanization.
And some of these urban areas or cities are quite far away from areas where water is available
so we need to transport water over a large distance, a long distance like for example
Chennai city in Tamil Nadu the water gets transported all the way from Krishna through
canals from Krishna river, and again from South from Cauvery it gets transported through
pipes, there is a long distances because the available water in Chennai city itself cannot
meet the demand, so there is a demand aggregation, there is a change in lifestyles also due to
increase in the per-capita income from $468 to 17,366 by expected to be by 250, so this
increase in per-capita income or increase in wealth will definitely put make people
demand more water, for example the present demand is only 90 liters per capita per day
which is almost 5 times less than what they use in United States of America with increase
in the per-capita income so the demand per person per day will also increase significantly,
so that's another driver for increase in water demand.
Now they'll be an increase in demand due to industrialization as more and more industries
come up, particularly power, steel, and other heavy industries require lot of water, so
there is going to be increase in water demand because of industrialization, we'll compare
based with how much water is available, but before that 1700 meter cube per year per person
if a country has less than that 1700 meter cube per year per person, then it is designated
as water stress country, if it is less than 1000 meter cube per year per person the country
would be designated as water scares, let's see what is the gap in the demand and supply
in our country, in India.
Here I am showing the map of India, the river valleys I mean river basins by 2030 there
will be severe demand supply gap in almost all river basins except the Northeast and
then maybe this, there is one river basin here Suvarna Rekha there also we won't have
that much of demand supply gap, and some paths here we won't have demand supply gap, but
in all the other river basins we are going to have demand supply gap.
Some river basins like Godavari would have moderate but other places other river basins
will have a very severe demand supply gap, and we have to consider that in our planning,
even before that the situation at present itself we have lot of issues as far as urban
water supplies concern, we have 31% gap in demand and supply of water
and most of the cities we have only intermittent water supply, in fact majority and more than
90% of the cities India have intermittent water supply, where the water is supplied
only a few hours in a day and in some places in fact it supplied maybe few hours in 3 or
4 days, very, very few locations we have 24/7 water supply, now this is an important point
to be consider because we would like to in near future actually supply water around the
clock that is 24/7, how do we make this transition?
That's something we have to think about, then more than 70% gap in the treatment of sewage
generated and treated, now this is also a very important point because if the wastewater
that is generated, the domestic wastewater that is generated is not treated and let into
the environment it is going to pollute our surface water sources as well as ground water
sources, so water will not be available, if the present scenario of not treating 100%
the domestic sewage goes on.
There is a more than 30% gap in the treatment of industrial wastewater generated and treated
there we are doing better than the domestic wastewater but still there is a gap we are
not treating all the industrial wastewater that is being generated, other than this we
have poor operational and financial health of the utility companies, the urban I mean
urban local bodies we call ULB's who are in charge of supplying this municipal water,
not many water connections are metered so we are not even knowing how much of water
we are supplying so we will not be able to collect the money from the, you know the people
for the water that is supplied to them because not many water connections are metered.
And there is a significant loss of water through leakage as much as it is estimated that as
much as 30 to 40% of water that is putting to a distribution system is being lost, they're
unable to account for that, so these are some of the key points which should be addressed
if you want to do a sustainable management of water in urban areas at least in India,
so there were quite a few issues flagged by planning commission, the oswel
planning commission in the 12th plan for water management, these are very important points,
it has been said that estimates of water availability, these estimates themselves are quite optimistic,
and another important point is water sector needs better regulatory framework, there is
a need for passing new groundwater loss and there is a need for setting up water regulating
authorities in each state, and we have to pass national water framework law, these are
something we need to do.
And now that's what they said in 12th plan, we have to manage in industrial and urban
water demand this is a very key point, manage industrial and urban water demand through
water recycling and reuse and rationalized user charges, these two need to be implemented
for sustainable water management in urban areas.
In this context I would like to introduce to you the concept or principles of Integrated
Water Management or IWM, the objectives of an Integrated Water Management are manage
water in an integrated way recognizing that it has multiple uses, water can be used for
many purposes, for example water is required for large amount of water is required for
carrying on agricultural activities for food production, in fact in India more than 80%
of the water is used in the, for irrigation, for agriculture, then water can be used, I
mean needs to be provided for drinking or domestic water supply although its only about
6% but this is a must, we need to provide this 6% I mean we need to provide water supply
to all the people, both urban and rural areas, then we need water for running our industries
particularly power and other heavy industries at the same time we should not take out all
the water that is available in a river and then make it dry, we need to make some water
run in the rivers, there is a minimum amount that needs to be left in the river itself
for it to survive, these are minimum ecological flows that need to be maintained in the rivers,
for maintaining the ecology, so there are multiple uses of water and one has to recognize
that while doing the management of water in any large catchment areas or integrated water
management in a basin, and we have to manage at the lowest appropriate level, when I say
at the lowest appropriate level means for example
when the water is taken for agricultural use, it's not just that we worry about how to operate
a reservoir, but we also need to intervene at the field level, at the field level, at
the lowest level that is we may go and then say how best to utilize the water in a farm
or in an agricultural field by going for better water delivery system to the plant zone, I
mean root zone of the plants, like here I'm showing a picture of a drip irrigation system
here, which probably has a better water use efficiency than the regular or conventionally
followed flood irrigation system or other surface irrigation systems.
Or we have to go and then intervene at the household level and then probably monitor
how much of water is being used for what purpose and then how to improve the efficiency of
water use at the household level itself, here I'm showing how to put the meters, this is
important because as I mentioned earlier in many of the urban areas in India we don't
have meter connections, so you have to manage at the lowest appropriate level, we also have
to consider the interest of all stakeholders, this is the picture from one
of the towns in India during summer and people don't have pipe water supply coming to the
houses, they go to the nearby public tap and then queue up their water pots, what I'm trying
to tell is we need to supply water to under privileged communities in urban areas as well
as in peri-urban areas and of course in rural areas as well as we have to supply water to
probably to swimming pools in star hotels, we have to consider the interest of all stakeholders.
The main issue is, the main point here is water should be recognized and treated as
an economic good, if you want to follow the principles of IWM, and what are the strategies
that one can adopt, we have to evolve viable and sustainable future for all the stakeholders
in the entire basin not just path of the basin and not for only few stakeholders and not
just for now but for the future also, viable, sustainable future for all the stakeholders
in the entire basin and this is very important, provide equitable access for water for all
the stakeholders, for this we need to do some demand management particularly demand management
for efficient utilization, for example right now in India the water use efficiency in agricultural
sector is very low is less than 30%, now we need to change our ways of irrigation and
how we deliver water to the root zone of the plants, and we need to increase irrigation
application efficiencies so that for the same amount of water we can grow more crops or
for growing the same amount of food we require less water, this is absolutely necessary.
So here we are showing a sprinkler system as an example for demand management, another
picture I'm showing here is schematic of a rainwater harvesting system for a house, whatever
the rain falls on the roof of the house we can take it through the pipes and then we
can signed it through some a sand filter and then stored that water in a concrete tank
underground when the rain falls we can stored that water and then use that water, pumped
that water back to the house through a treatment system and then we can use it for even drinking,
if you do that then this particular household would not demand water from the utility, would
not demand as much of water from the utility company, so that way the demand we can reduce
the demand so that whatever that is available to us with the city it can be used more fairly
and more efficiently, so there is a demand side management one has to implement.
We need to prevent further environmental degradation, there are some, not all the rivers are bad
or dirty or having poor quality of water, there are some rivers which are cleaned, which
are pristine, we have to make sure that there is no further environmental degradation, we
have to prevent pollutants moving into the river and then we have to regulate the activities
in the nearby zones so that the river does not get polluted, we also have to restore
degraded water resources, this picture I have shown earlier also in one of my lectures very
bad quality river in Chennai and we have to restore such rivers, restore degraded water
resources and implementation of programs certain principles have to be followed, the
overall strategy should be very clearly define, should very clearly define what are the objectives
any new water resources project that is coming up in the urban areas, it should clearly define
the objectives what are the delivery mechanisms and very important a monitoring schedule,
that is once you put in this system we have to monitor that, and to see whether it is
functioning properly or not, so the planning is a crucial step for all these big water
resources projects in urban areas and not only planning of course after they are putting
in the place we have to properly monitor, in fact most of the water distribution networks
these days is mandatory to have this data that is supervisory controlling data acquisition
system which tells you how this system is performing.
We have to recognize the importance of research to access the resource base and evaluate linkage
between water resources and the impacts on environment and socio-economy this cannot
be over emphasized, the research is very important and the research needs to be carried out in
the laboratories as well as in the field to get better understanding of the linkage between
water resources, the environment and the socio-economy, more research needs to be done, like for example
I just give you an example of a research that we are carrying out in terms of leak detection
in large water already existing water distribution networks but where the instruments are not
in placed.
And we are interested in finding out the areas where the leakage could be much more than
the areas, maybe this area in water distribution network is having lot more leakage of water
compared to some other area, if you can find out the answers to such questions than probably
we can prioritize our maintenance probably if this area is leaking more I would go and
then change the pipes in that area rather than change the pipe somewhere else, how do
we do this?
If it's a large water distribution network, as I mentioned we do not have any instruments
already there in place in the system, and we have to go and then make measurements and
this measurements cost lot of money and then take lot of time, so what is the kind of we
measurement schedule we can have to detect the areas where the water is leaking more,
we need to do research in such, I mean we need to research to find such, answers to
such questions.